Self-powered tyre sensors

has developed technology which can power car tyre pressure monitoring systems (TPMS) using wheel movement instead of batteries.

The device, a piezoelectric bimorph, enables TPMS manufacturers to design self-powered remote sensors that accurately measure tyre pressure, with none of the lifetime and disposal issues associated with batteries.

The Worcestershire company’s energy-scavenging bimorphs are based on established piezoelectric technology, whereby the movement of the wheel and pressure of the tyre as it hits the ground causes the bimorph to bend and undergo stress, which is then transformed into electrical energy. The bimorphs generate enough electrical energy to power a wireless signal that transmits valuable data about the pressure in the tyre to an on-car receiver.

‘It is now mandatory in the US for all new cars to have a tyre pressure monitoring system installed.’ said Ian Edwards, general manager at Morgan Electro Ceramics.

‘This is something that has been driven by safety concerns, related to under inflated tyres, but also fuel efficiency and tyre life expectancy. At the moment batteries are used to power the sensor and wireless transmitter, but they have limited life and will be required to be replaced and disposed of throughout the life of the vehicle. Our piezo bimorphs give reliable performance that will last the life of the vehicle and therefore greatly reduce on-going costs and reduce the environmental waste.’

Piezoelectric bimorphs also support the development of an intelligent TPMS, which would be capable of collecting more data about the tyre and road conditions and communicating with other systems within the vehicle.